mfbt/Range.h
author B2G Bumper Bot <release+b2gbumper@mozilla.com>
Wed, 26 Nov 2014 04:41:58 -0800
changeset 242028 3098b45e9a24dc42213a0240d82620dfada6193b
parent 214333 91d7659bb35145e10ff737753688e0972c1a79b5
child 248970 3928ee1b0381453833c00fbe1e1b72a26143f13a
permissions -rw-r--r--
Bumping manifests a=b2g-bump

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_Range_h
#define mozilla_Range_h

#include "mozilla/NullPtr.h"
#include "mozilla/RangedPtr.h"

#include <stddef.h>

namespace mozilla {

// Range<T> is a tuple containing a pointer and a length.
template <typename T>
class Range
{
  const RangedPtr<T> mStart;
  const RangedPtr<T> mEnd;

  typedef void (Range::* ConvertibleToBool)();
  void nonNull() {}

public:
  Range() : mStart(nullptr, 0), mEnd(nullptr, 0) {}
  Range(T* aPtr, size_t aLength)
    : mStart(aPtr, aPtr, aPtr + aLength),
      mEnd(aPtr + aLength, aPtr, aPtr + aLength)
  {}

  RangedPtr<T> start() const { return mStart; }
  RangedPtr<T> end() const { return mEnd; }
  size_t length() const { return mEnd - mStart; }

  T& operator[](size_t aOffset) const { return mStart[aOffset]; }

  operator ConvertibleToBool() const { return mStart ? &Range::nonNull : 0; }
};

} // namespace mozilla

#endif /* mozilla_Range_h */